1. Field of the Invention
The present invention relates to a respiration control apparatus for controlling the respiration of a respiratory moving object in a controlled body such as a human body during examination or treatment.
2. Description of the Related Art
In recent years, computer-assisted diagnosis apparatus such as CT (Computed Tomography) apparatus, CR (Computed Radiography) apparatus, MRI (Magnetic Resonance Imaging) apparatus, and radiation treatment apparatus for treating patients by applying radiation to local body regions have widely been used in the medical field.
A respiratory moving object such as an organ in a human body to be diagnosed by a computer-assisted diagnosis apparatus or treated by a radiation treatment apparatus, changes its position or volume greatly as the human body breathes. Therefore, when the computer-assisted diagnosis apparatus images the respiratory moving object, the produced image tends to be low in quality, or when the respiratory moving object is treated by the radiation treatment apparatus, the irradiation range of radiation is liable to change.
In view of the above drawbacks, various apparatus for detecting a moving state of a respiratory moving object, predicting a position of the respiratory moving object based on the detected moving state, and applying radiation at a given time based on the predicted position have been proposed. For example, Japanese laid-open patent publication No. 2000-262513 discloses an X-ray computed tomographic imaging apparatus having a respiration sensor to be attached to a human body to be imaged. The disclosed X-ray computed tomographic imaging apparatus applies X-rays to an organ in the examinee during an inhaling period in which the volume of the organ is stable, based on an output signal from the respiration sensor, and collects image data from the organ based on the applied X-rays.
However, the conventional X-ray computed tomographic imaging apparatus may not be able to collect optimum image data from a human body because the respiratory state of a human body widely differs depending on the age and the physical or mental condition of the human body. Also, the output signal from the respiration sensor widely differs depending on how the respiration sensor is attached to the human body.